Which of the following combinations of items would require pharmacist referral?

The combination of polyethylene glycol/propylene glycol artificial tears and diphenhydramine would require pharmacist referral because these products can interact in ways that may lead to increased drowsiness or potential adverse effects in certain patients, especially those who may be sensitive to the sedative effects of diphenhydramine. Diphenhydramine is an antihistamine that has notable sedative properties, and when combined with artificial tears that contain polyethylene glycol and propylene glycol, there may be concerns regarding the patient's ability to perform tasks that require full alertness, such as driving or operating machinery.

In situations where a patient is considering using both items, the pharmacist can evaluate the individual's medication history, current prescriptions, and overall health status to ensure that the combination is safe and appropriate for them. This referral process helps ensure patient safety and optimize therapeutic outcomes by providing an opportunity for counseling and education regarding the proper use of both products.